I had a couple of kids who did that to me when I was growing up. I didn't have anything to do with them after the first time. Maybe they're insecure about being tough so they do that stuff to try to prove that they can kick your butt. I think they try to intimidate you. It's ridiculous.
I had a step-father who use to punch me and my sisters really hard in our arms when we were young. He would do it for no reason at all except to be mean. He'd say he felt like doing that and then do this stupid laugh. One of our uncles saw him do it to my 2nd oldest sister and he went off on him. So he stopped doing that and started doing other things.
Please remember no one is perfect, we all make mistakes and be a little nicer to yourself. 
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Whatever you think you can do, or dream you can, begin it. Boldness has genius, magic and power in it. ~Goethe
Your Aspie score: 167 of 200
Your neurotypical (non-autistic) score: 35 of 200
You are very likely an Aspie.